Method and apparatus for making springs



H. OHLAU.

METHOD AND APPARATUS FOR MAKING SPRINGS. APPLICATEON FILED JAN 13. 1919.

1,368,808. I Patented Dec-28,1920.

MM W- ATTORNEY UNITED STATES PATENT OFFICE.

HENRY OHLA'U, OF IRONDEQUOIT, NEW YORK, ASSIGN OR TO GENERAL RAILWAY SIGNAL COMPANY, OF GATES, NEW YORK, A CORPORATION OF NEW YORK.

METHOD AND APPARATUS FOR MAKING SPRINGS.

Application filed January 13, 1919.

To all '20 [tom it may concern Be it known that I, HENRY OHLAU, a citizen of the United States, and resident of the town of Irondequoit, in the county of Monroe and State of New York, have invented a new and useful Method and Apparatus for Making Springs, of which the following is a specification.

This invention relates to a method and apparatus for making springs having uniform strength and dimensions under compression or deflection, and is applicable more especially to the making of light compression coil springs for use in delicate instruments like relays.

In making small coil springs, it is impracticable to coil the short lengths of small wire so that the length and strength of the springs produced will be uniform. Even when the wire is coiled into a long spring and the desired short lengths are cut off, it is found that the strength or pressure will vary through comparatively wide limits, too great for practical use in accurate and delicate instruments. For one thing, the size and resiliency of commercial spring wire is variable so that springs of the same length, with the same number of coils and the same pitch will not have exactly the same strength. Likewise, it is impracticable to coil small spring wire into a spring of small diameter with a uniform and even pitch by ordinary machinery and commercial manufacturing methods, such that the same number of coils are included in the same unit length.

iVith these considerations in view, one of the objects of my invention is to provide a novel method which can be readily practised by average skilled labor and which may be used to produce small coil springs capable of producing uniform pressure when compressed'to the same length. My invention also contemplates a simple and cheap apparatus for practising this method.

Other detail objects and advantages of my invention will appear as the description progresses, and the novel features of my invention will be pointed out in the appended claims.

In describing my invention, reference will Specification of Letters Patent.

Patented Dec. 28, 1920.

Serial No. 270,994.

of making springs, in which like reference characters refer to like parts in the several views, and in which Figure 1 is a perspec-, tive view of the preferred embodiment of my apparatus; Fig. 2 is a fragmentary horizontal section through the apparatus shown in Fig. 1; and Figs. 3 and 4 are fragmentary views, partly diagrammatic, for illustrating significant features of my invention and for aiding in the explanation of my method.

My method, in its broadest aspect, is applicable to the making of Various forms of springs, but I will explain the features of my invention more particularly in connection with the making of short lengths of light compression coiled springs. Spring wire of the proper size and resiliency is first coiled in the usual way into long pieces of spring with the desired spacing and pitch of coils, each piece being as many times longer than the length of the finished spring desired as it is convenient to work. From each long piece the proper number of coils or turns, or fractions of a coil, are cut, such that the several severed portions will be capable of exerting a predetermined pressure when compressed to a predetermined length. The method employed in cutting 01f the proper short lengths from the longer piece of spring can be more readily understood and appreciated by consideration of the construction and mode of operation of the specific form of apparatus which I have devised for practising this method.

Referring to the accompanying drawings, the preferred embodiment of my apparatus illustrated comprises abase block A, in the upper face of which is formeda lengthwise groove 1 with the rounded bottom adapted tosupport the long piece of spring S, as shown in Fig. 1. Near oneend of this groove 1, is an insert 2 of hardened steel, which terminates in a cutting edge 3. This cutting edge 3 is preferably inclined at an angle to the axis of the groove 1, for the reason more fully explained hereinafter. A cutter, or knife holder, C is pivotally supported at its lower corner by a pin 4 (see Fig. 2). This pivotal support may be made in various-ways, but in the construction I employ, the pin 4 has a driving fit in said cutter C and is journaled at its ends in the main body portion of the base'block A and an upwardly extending lug 5 integral therewith. Opposite the lug 5 is a similar lug 5 and when the cutter C is thrown forward, it fits between the base block A and the lug 5 so as to be held against sidewise spring on the pin 4, This cutter C is shaped, as illustrated, to provide a handle for its manipulation.

In the lower end of the cutter C is formed a lengthwise rectangular recess 6, in which a knife 6 is fastened by screws 7 or other suitable means. This knife 6 is intended, as explained hereinafter, to pass into the space between the coils of the spring; and in order that it may be sufficiently thin for this purpose, and also have sufficient strength, I preferably form this knife from a piece of sufiicient thickness for the requisite strength and then cut away a U- shaped part, as indicated by the numeral 8, to leave a thin blade 6 (see Figs. 3 and l) of sufficient length and width to pass between coils of the spring. It will be observed that this construction reinforces the thin blade 6 at its top and edges. The cutter C also has a U-shaped portion cut out of its lower end, so as to allow the end of the cutter to set down over the spring and per mit the blade of the knife to pass between the coils of the spring.

At one end of the base block A is an upright standard or end post 13, which is fastened at its lower end to said base block by a cap screw 9 and dowel pin 10 (see Fig. 2). Fixed in this end post B is a pin 1.1, on which is journaled a collar or hub 12, held in place by a sleeve 13- clamped to said pin by a set screw in an obvious manner. Fastened to this hub 12 in any suitable manner, is a downwardly extending operating arm 14, the lower end of which is bent horizontally and is attached to an enlarged head 15, having integral therewith a conical guiding projecti on 15 This guiding projection 15 is made to slip loosely into the open end of a coil spring of the size to be made (see Fig. 3). Also fixed to the hub 12 is an upwardly extending pointer 16, which is limited in its sidewise movement by stop pins 17 secured in the end post B. A fixed index or marker 18 for coacting with the pointer 16', is fastened to the end post B. Also fixed to the hub 12 is a horizontally extending weight arm 19 upon which is slidably mounted a weight 20, said weight 20 being clamped in any desired adjusted position by a suitable set screw. I

Pivoted at its lower end on a horizontal pin 21 fastened in the-base block A, is a retaining lever or cam 22', which is adapted to be moved back and forth by' hand about the tion, when the latter drops in a shallow notch 23, formed in the edge of said retaining lever.

In using the apparatus shown and described to practice my method, the retaining lever 22 is thrown forward to the position shown in Fig. 1, to raise the weighted lever 22 and hold it in the raised position, thereby holding the pointer 16, the arm 14, and the head 15' in the position shown. The cutter C is thrown back, and the long piece of spring S in the groove 1 is advanced until its end bears against the head 15. The cutter C is now thrown forward so that the thin blade 6 of its knife passes between the coils of the spring, as shown in Figs. 3 and 4:.

It is noted here that the pin 4 on which the cutter C is pivoted is inclined at such an angle relative to the axis of the groove 1, that the blade 6 of the knife moves downward in a plane between two of the coils of the spring, so that this blade may pass freely between the coils-, as shown in Fig. l. The cutting, edge 3 of the insert 2 is inclined to the axis of the groove 1 in a like manner, so that the blade 6 of the knife may pass over this cutting edge with a shearing action. I have shown the pin 4 inclined so that the knife 6 is inclined to the axis of the spring when looking. down on the spring (see Fig. 4), but is at right angles to the axis of the spring when looking sidewis'e at the spring. (See Fig. If desired, however, on ac count of the pitch of the coils, or any other reason, the pin 4 may be inclined so that the movement of theblade of the knife conforms more clearly to the inclination of the coils of thespring.

Returning to the manipulation of the apparatus, the cutter C ismoved forward carefully so that the blade of the knife passes into the full depth of the spring without actually cutting it (see Fig. 3). The retaining lever 22- is now thrown back, thereby releasing the weight 20. There is now a portion of the long piece of spring, S which is distinguished or segregated from the rest, so far as its strength or tension is concerned, without being, physically separated. Consequently, the strength and length of this segregated portion under compression inay be measured. In the apparatus illustrated, one end of the segregated portion abuts against the bladeof the knife 6, and the other end bears against the head 15-. Thus, this'segregated portion is placed under a compressing force exerted by the weight 20, and the length of this portion under compression is the distance between the knife 6 and the head 15. When the pointer 16 is opposite the marker 18,,thedistancebetween the head15 and theblade of the knife 6 corresponds with the desiredcompressed length of the finished spring.

Consequently, with theweight20 adjusted to apply the desired compressing force against this segregated portion of the longer piece of spring, the next thing is to vary the num ber of coils or fractions thereof included in the segregated portion between the knife 6 and the head 15, such that these coils will have the desired length under compression. To accomplish this adjustment, the spring S is turned or twisted by hand, and as a result is advanced or retracted gradually past the blade 6 of the knife, in much the same way as a threaded bolt is advanced or retracted by turning it in a tapped hole. In other words, the spring is screwed past the blade 6 of the knife, so as to speak, and as a result more or less number of coils of the spring are included in the space between the knife and the head 15. Obviously, as more coils of the spring are included in this space, the pressure which this segregated portion of the long spring S exerts against the head 15 is increased, the other end of this segregated portion reacting against the blade of the knife. In this way, the spring S may be rolled back and forth as desired, until the pressure exerted by segregated portion .against the head 15 exactly balances the weight 20, this point being determined by the pointer 16 coming opposite the marker 18. Ilind it preferable after this initial adjustment has been made, to raise the weight 20, and then allow it to settle back again, this operation being repeated once or twice until it is assured'that the segregated portion of the spring between the knife blade 6 and the head 15 has the desired strength. As soon as the correct number of coils or fractions of a coil needed to produce the desired strength have been determined, the stroke of the cutter C is completed, and the selected portion of the spring cut oil. It will be evident that the knife 6 and cutting edge 3 act to give the spring a squared end. The operation of making a finished spring of a predetermined length and the proper strength is now completed.

To repeat the operation, the retaining lever 22 is thrown forward to lift up and support the weight 20, the cutter C is thrown back, the severed portion of the spring removed, the remaining long piece of spring advanced, and then the sequence of movements previously described repeate From a consideration of the various steps described for cutting off a portion of a longer spring, it will be evident that the severed portion constituting the finished spring, will have a predetermined length and a predetermined strength. The length of the severed portion is fixed by the distance between the blade of the knife 6 and the head 15, when the pointer 16 is opposite the marker 18. The desired tension is fixed by the adjustment of the weight 20. Since these factors are determined exactly for each spring, uniform length and strength is obtained, in spite of the fact that the diameter and resiliency of the spring wire used may vary slightly, and the pitch or number of coils per unit of length may vary.

The apparatus shown and described is intended to be a simple embodiment, and it is obvious that various modifications and elaborations may be made, without deviating from the characteristic features of my invention. Also, this apparatus exemplifies the practice of my method only to compression coil springs and is obviously susceptible to various changes without departing from my invention. I wish it to be understood, therefore, that the accompanying illustration and description selected is merely illustrative of the nature of my invention; and that I claim as my invention anything coming within the scope of the appended claims.

hat I claim is 1. The method of making springs of a uniform strength when deformed to a predetermined dimension, which consists in forming material into the shape of the finished spring desired and in a large piece suflicient to make a number of finished'springs, then predetermining by actual test and adjustment the portion of said large piece which is capable of exerting the desired pressure when deformed to the desired dimension, and finally cutting off the portion thus determined.

2. The method of making springs of a uniform strength when deformed to a predetermined dimension, which consists in forming a large piece of material suflicient to make a plurality of finished springs, segregating the end portion of the large piece without physically separating said portion and applying a predetermined deforming force to said segregated portion, adjusting said segregated portion until it is capable of exerting the desired pressure when deformed to the desired dimension, and finally cutting oil the portion thus predetermined.

3. The method of making compression coil springs of uniform strength and length which consists in coiling wire into a long spring, predetermining by adjustment and actual test the numberof coils or fractions thereof required in an end portion of said long spring to exert the desired pressure when compressed to the desired length, and then cutting off the end portion thus determined.

4. The method of making compression coil springs of uniform strength and length which consists in segregating a portion of a longer spring without physically separating such portion, applying a predetermined compressing force to such segregated portion, adjusting the number of coils or fractions thereof included in said segregated portion until it is of a predetermined length under compression, and then cutting off the number of coils thus selected.

space between the coils until the end portion of the spring at one side of said member is capable of exerting a predetermined pressure when compressed to a predetermined length, and then cutting oif the portion thus selected. 7

7. The method of making compression coil springs of uniform strength and length which consists in coiling wire into a long spring, inserting a member into the space between the coils of the spring near one end so as to segregate an end portion from the main body of the spring which can be separately compressed applying a compression force to this endportion corresponding to the strength of the finished spring desired, adjusting said member and long spring relatively to each other lengthwise of the spring to vary the number of coils or fractions thereof in the segregated end portion until said end portion has a predetermined length under compression, and then cutting off the end portion thus determined.

8. The method of making compression coil springs of uniform strength and length which consists in coiling wire into a long spring, segregating without physically separating a portion of the long spring, applying a compressing force upon said segregated portion corresponding to the strength of the finished spring desired, varying the number of coils included in said segregated portion until said portion has a predetermined length, and then cutting off the por tion thus determined.

9. Apparatus for making compression coil springs of uniform strength and length out of long springs, comprising a member adapted to pass into the space between the coils of the long spring and constitute an abutment against which an end portion of the spring on one side thereof may be separately compressed, means for applying a compressing force to said end portion, and means for indicating when the portion under compression has a predetermined length.

10. Apparatus for making compression coil springs of uniform strength and length out of long springs, comprising a member adapted to enter the space between the coils of the long spring, means for applying a predetermined compressing force to the spring at one side of said member, means for indicating the length of the portion under compression, and means including said member for cutting the spring.

11. Apparatusfor making compression coil springs of uniform strength and length out of long springs, comprising cutting means including a knife adapted to enter between the coils of the long spring so as to form a fixed abutment past which the spring may be moved lengthwise by'turning it, and means for indicating when the portion of the spring of the predetermined length on one side of the knife is capable of exerting a predetermined pressure corresponding to the strength of the finished spring desired.

12'. Apparatus for making compression coil springs of uniform strength and length, comprising cutting means including a knife adapted to enter the space between the coils of the long spring to the full depth thereof near one end means including a movable member arranged to bear against the end portion of the long spring at one side of the knife, for applying a predetermined compressing force to said end portion; and means for determining when the knife and said movable member are spaced a predetermined distance apart.

HENRY OHLAU. 

